Articles having an odor control system comprising a cationic polysaccharide and an odor controlling agent

ABSTRACT

The present invention relates to articles suitable for controlling odors, especially odors associated with bodily fluids, which comprise a cationic polysaccharide, preferably chitosan material, together with an odor controlling agent, preferably an odor absorbent agent and/or a chelating agent. This combination provides synergistic reduced odor control towards malodors associated with bodily fluids like menses.

CROSS REFERENCE TO RELATED REFERENCES

[0001] This is a continuation of International ApplicationPCT/US01/13062 with an International filing date of Apr. 23, 2001.

FIELD OF THE INVENTION

[0002] This invention relates to articles, such as absorbent articles,for controlling odors, especially odors associated with bodily fluids,comprising a cationic polysaccharide, preferably chitosan material,together with an odor-controlling agent.

BACKGROUND OF THE INVENTION

[0003] Malodors may be present in the environment from numerous sourcesboth animate and inanimate. Many products and articles are availablewhich aim to avoid or minimize the detection of such odors. Inparticular, it is particularly desirable to provide odor controllingmaterials to address the malodors which are generated by the human body,or from bodily fluids such as perspiration, urine, faeces, menstrualfluids, vaginal fluids and the like.

[0004] Articles like absorbent articles for example are designed to beworn by humans to absorb bodily fluids, such as urine, menstrual fluidand perspiration, etc. Examples of absorbent articles include sanitarynapkins, pantiliners, disposable diapers, incontinence pads, tampons,perspiration pads, nursing pads and the like.

[0005] In use, the absorbent articles are known to acquire a variety ofcompounds, for example volatile fatty acids (e.g. isovaleric acid),ammonia, amines (e.g. triethylamine), sulphur containing compounds (e.g.mercaptans, sulphides), alcohols, ketones and aldehydes (e.g.,furaldehyde) which release unpleasant odors. These compounds may bepresent in the bodily fluid or may be developed by chemical reactionsand/or any fluid degradation mechanisms once the bodily fluid isabsorbed into the absorbent article like for example a feminine pad. Inaddition bodily fluids usually contain micro-organisms and/or enzymesthat can also generate malodorous by products as a result of degradationmechanisms like putrefactive degradation, acid degradation, proteinsdegradation, fat degradation and the like. Unpleasant odors, whichemanate from absorbent pads when in use, may make the wearer feelself-conscious.

[0006] Various odor-controlling materials have been disclosed in the artto combat some of the unpleasant odors referred to above. Indeedsolutions have been provided that use different technical approacheslike masking, i.e., covering the odor with a perfume, or absorbing theodor already present in the bodily fluids and those generated afterdegradation.

[0007] Most of the focus in the prior art is found on the odorabsorption technology. Examples of these types of compounds includeactivated carbons, clays, zeolites, silicates, starches, cyclodextrine,ion exchange resins and various mixture thereof as for example describedin EP-A-348 978, EP-A-510 619, WO 91/12029, WO 91/11977, WO 89/02698,and/or WO 91/12030. All of these types of odor controlling agents arebelieved to control odor by mechanisms whereby the malodorous compoundsand their precursors are physically absorbed by the agents and thus suchagents hinder the exit of the odor from articles like absorbentarticles. However, such mechanisms are not completely effective as theformation of the odor itself is not prevented and thus odor detection isnot completely avoided.

[0008] Thus although these materials provide some control of odorsassociated with bodily fluids, there still exists a need of furtherimprovement in terms of odor control over a wide range of malodorouscompounds.

[0009] It is an object of the present invention to provide effectiveodor control over a wide range of malodors. More particularly, it is anobject of the present invention to provide articles, especiallydisposable absorbent articles, which deliver outstanding odor controlover a broad spectrum of malodors.

[0010] It has now been found that the above needs can be addressed bycombining a cationic polysaccharide together with an odor-controllingagent, as the odor control system for an article, preferably adisposable absorbent article.

[0011] It has surprisingly been found that the combination of an odorcontrolling agent, typically an odor absorbent agent (e.g., zeoliteand/or cyclodextrin) and/or a chelating agent (e.g., ethylene diaminetetracetate (EDTA)) together with a cationic polysaccharide, preferablychitosan material, in an article, like an absorbent article, typicallycoming into contact with bodily fluids, results in a synergistic effectin terms of odor control. Indeed this combination gives more odorreduction than the odor reduction associated with the use of one ofthese two classes of ingredients alone at the same total level (eithersaid odor controlling agent alone or said cationic polysaccharide alone)in an absorbent article contacted with bodily fluids.

[0012] Actually the combination of a cationic polysaccharide with anodor-controlling agent in an article herein allows combining odorcontrol mechanisms by which the overall malodor detection issynergistically reduced or even prevented.

[0013] Without to be bound by any theory it is believed that cationicpolysaccharides, preferably chitosan materials, provide odor control ofmalodorous components associated with bodily fluid by multiplemechanisms.

[0014] Firstly, the odor absorption and retention characteristics ofpolysaccharides are due to the presence in the polymer structure ofionisable cationic functional groups. These groups are usually ammoniumgroups, a high proportion of which are in the salt form when the polymeris dry but which undergo dissociation and salvation upon contact withbodily fluid. In the dissociated state, the polymer chain will have aseries of functional groups attached to it which groups have the sameelectric charge (e.g., —NH₃ ⁺ ⁺H₃N—) and thus repel one another. Thisleads to expansion of the polymer structure, which, in turn permitsfurther absorption of negatively charged odorous molecules and thus thecontrol thereof.

[0015] Secondly, the positively charged cationic groups of thepolysaccharides will interact with negatively charged anionicfunctionalities present in bodily fluids, like the carboxylic groups ofproteins or hydroxylic acid bearing entities like short chain acid(e.g., butyric acid). This will result in the formation oftri-dimensional net between cationic polysaccharides and such moleculeswith anionic groups (gelification of the bodily fluids). Thisgelification will entrap most odorous molecules (like lipids, acids)thereby controlling malodor.

[0016] Thirdly and more importantly the cationic polysaccharidesespecially the aminopolysaccharides (chitosan materials) are believed toact as antimicrobial agents. Indeed the polysaccharides with theirpositively charged cationic groups will interfere with negativelycharged surface of microorganism walls, thereby inhibiting the growth ofsuch microorganisms or even killing such microorganisms. These cationicpolysaccharides will also interfere with negatively charged surface ofenzymes, thereby inactivating the enzymatic activity, which, like themicrobial activity, are otherwise responsible for the formation ofmalodorous components. The cationic polysaccharides like chitosanmaterials further act by their indirect antimicrobial activity bylinking some of the microorganism nutriments like lipids and/orminerals.

[0017] Surprisingly, the presence of the cationic polysaccharide, likechitosan material, increases the effectiveness of odor controllingagents like odor absorbent agents. Without to be bound by any theory itis speculated that the cationic polysaccharides herein, typicallychitosan materials, control enzymatic and microbial growth and as aconsequence the amount of malodorous compounds associated with theenzymatic and microbial activity occurring in bodily fluid. In otherwords, the cationic polysaccharides reduce or even prevent the formationof malodorous compounds, thereby reducing the total amount of malodor tobe controlled. This allows the odor-controlling agent, typically theodor absorbent agent (e.g., zeolite and/or cyclodextrin) to work inreduced amount of active. Actually this results in a more effective aswell as a sustained use of the odor-controlling agent herein. Indeed thesaturation point of the odor absorbent agents when used in associationwith the cationic polysaccharides herein will be reached after prolongedperiods of use, typically after prolonged wearing time of an absorbentarticle (pantiliner, pad) coming into contact with bodily fluid, ascompared to when used alone in absence of the cationic polysaccharidesin the same conditions.

[0018] Advantageously it is believed that the odor controlling agents,typically the odor absorbent agents, also help the cationicpolysaccharides in reducing malodor by adsorbing not only odor presentin the bodily fluids but also volatile odor present in the head space(space between the absorbent article and the urogenital surface). Thiscombination is thus active too towards volatile malodor components,which escape from the bodily fluids and hence would not come in directcontact with the polysaccharides. Actually this combination allows odorcontrol over a wider range of malodorous components, which wouldotherwise not have been fully controlled by one of these two classes ofingredients used alone.

[0019] Surprisingly the presence of a chelating agent on top of thecationic polysaccharide, namely chitosan material, results in increasedantimicrobial properties. Without to be bound by any theory it isbelieved that the chelating agents used herein complete theantimicrobial properties of the cationic polysaccharides, by theirindirect antimicrobial activity. Indeed the chelating agents have theability to link some of the microorganisms nutriments like positivelycharged growth factors, typically Ca⁺⁺, K⁺, Mg⁺⁺. Advantageously thecombination of these two preventing mechanisms results in a synergisticreduction in odor formation.

[0020] In a preferred embodiment herein the disposable absorbentarticles have an apertured polymeric film topsheet. This topsheetcontributes to further improve the odor control benefit.

[0021] In another preferred embodiment herein the disposable absorbentarticles have a breathable backsheet. This contributes to a furtherimproved odor control benefit. Even more preferred herein the disposableabsorbent articles have both a breathable backsheet and an aperturedpolymeric film topsheet.

[0022] The present invention is preferably directed to disposableabsorbent articles like pantiliners, feminine napkins, incontinent pads,diapers, tampons, interlabial pads, perspiration pads, surgical pads,breast pads, human or animal waste management devices and the like.Other articles suitable for use according to the present inventionfurther include articles designed to be contacted with the body such asclothing, bandages, thermal pads, acne pads, cold pads, compresses,surgical pads/dressings and the like, body cleansing articles likeimpregnated wipes/tissues (e.g. baby wipes, wipes for feminine intimatehygiene), articles for absorbing perspiration such as shoe insoles,shirt inserts, and the like, and articles for animals like litters andthe like.

BACKGROUND ART OF THE INVENTION

[0023] WO 99/61079 discloses odor reduction for products such asdisposable diapers and training pants, sanitary napkins and tampons bythe use of triglycerides and polyglycosides to enhance the malodorabsorption properties of compositions and substrates such as naturallyoccurring polymers like chitosan or alginates and synthetic polymerstreated with surfactants.

[0024] WO 99/32697 discloses that chitosan and chitin-based polymersexhibit increased antimicrobial activity when coated onto the surface ofa hydrophobic material such as polypropylene.

[0025] None of these references discloses absorbent articles comprisingcationic polysaccharides, typically chitosan materials, together with anadditional odor controlling agent, typically an odor absorbent agentlike zeolite and/or cyclodextrin, or a chelating agent like ethylenediamine tetracetate, let alone that such combinations result insynergistic malodor reduction.

SUMMARY OF THE INVENTION

[0026] The present invention relates to an article, preferably adisposable absorbent article, for controlling odors, preferably odorsassociated with bodily fluids, comprising a cationic polysaccharide andan additional odor-controlling agent. In a preferred embodiment of theinvention the article also comprises an absorbent gelling material.

DETAILED DESCRIPTION OF THE INVENTION

[0027] By “article” it is meant herein any three-dimensional solidmaterial being able to comprise a cationic polysaccharide and anodor-controlling agent. The term “disposable” is used herein to describearticles, which are not intended to be launched or otherwise restored orreused as an article (i.e., they are intended to be discarded after asingle use and, preferably to be recycled, composted or otherwisedisposed of in an environmentally compatible manner). The term“absorbent articles” is used herein in a very broad sense including anyarticle able to receive and/or absorb and/or contain and/or retainfluids and/or exudates, especially bodily fluids and/or exudates.

[0028] Preferred articles according to the present invention aredisposable absorbent articles that are designed to be worn in contactwith the body of a user and to receive fluids/exudates from the body,such as pantiliners, sanitary napkins, catamenials, incontinenceinserts/pads, diapers, tampons, interlabial pads/inserts, breast pads,human or animal waste management devices and the like. Typically suchhuman urine or faecal management devices comprise a bag having anaperture and a flange surrounding the aperture for preferably adhesiveattachment to the urogenital area and/or the perianal area of a wearer.Any faecal or urine management device known in the art is suitable foruse herein. Such devices are described in for example WO 99/00084 to WO99/00092. Other suitable articles according to the present inventionalso include other articles designed to be placed against or inproximity to the body such as clothing, bandages, thermal pads, acnepads, cold pads, compresses, surgical pads/dressings and the like,articles for absorbing perspiration such as shoe insoles, shirt inserts,perspiration pads and the like, body cleansing articles like impregnatedwipes/tissues (e.g. baby wipes, wipes for feminine intimate hygiene),and the like, and articles for animals like litters and the like.

[0029] By “bodily fluid and/or bodily exudate” it is meant herein anyexudate/fluid produced by human or animal body occurring naturally oraccidentally like for instance in the case of skin cutting, includingfor instance perspiration, urine, menstrual fluids, faeces, vaginalsecretions and the like.

Cationic Polysaccharides

[0030] According to the present invention the articles comprise as anessential component a cationic polysaccharide or a mixture thereof.

[0031] Suitable cationic polysaccharides for use herein are positivelycharged polysaccharides due to the presence of cationic functionalgroups. Suitable polysaccharides for use herein include natural andsemi-synthetic cationic polysaccharides. Examples of suitable cationicfunctional groups include primary, secondary or tertiary amine groups orquaternary ammonium groups, which should be present in base form.Preferably quaternary ammonium groups are present. The cationicpolysaccharides for use herein might be a fibrous polysaccharide such ascellulose with an excess of quaternary ammonium compound containing atleast one group capable of reacting with polysaccharide hydroxyl groups.Such cationic polysaccharides are described in WO 92/19652 and WO96/17681, herein incorporated by reference. Highly preferred herein areaminopolysaccharides, namely chitin-based materials, chitosan materialsand mixture thereof.

[0032] By ‘chitosan material’ it is meant herein chitosans, modifiedchitosans, crosslinked chitosans and chitosan salts.

[0033] Chitosan is a partially or fully deacetylated form of chitin, anaturally occurring polysaccharide. Indeed, chitosan is anaminopolysaccharide usually prepared by deacetylation of chitin(poly-beta (1,4)-N-acetyl-D-glucosamine).

[0034] Chitin occurs widely in nature, for example, in the cell walls offungi and the hard shell of insect and crustaceans. The waste fromshrimp-, lobster, and crab seafood industries typically contains about10 to about 15 percent chitin and is a readily available source ofsupply. In the natural state, chitin generally occurs only in smallflakes or short fibrous material, such as from the carapace or tendonsof crustaceans. There is generally no source, as with cotton in thecellulosics, that forms useful shaped articles without solution andre-precipitation or re-naturing.

[0035] More specifically, chitin is a mucopolysaccharide,poly-N-acetyl-D-glucosamine with the following formula:

[0036] wherein x represents the degree of polymerization. Although xcannot be determined precisely, x is believed to be commonly in therange of from about 30 to about 50,000. Chitosan is not a single,definite chemical entity but varies in composition depending on theconditions of manufacture. It may be equally defined as chitinsufficiently deacetylated to form soluble amine salts. Chitosan is thebeta-(1-4) polysaccharide of D-glucosamine, and is structurally similarto cellulose, except that the C-2 hydroxyl group in cellulose issubstituted with a primary amine group in chitosan. The large number offree amine groups makes chitosan a polymeric weak base. Solutions ofchitosan are generally highly viscous, resembling those of natural gums.

[0037] The chitosan used herein is suitably in relatively pure form.Methods for the manufacture of pure chitosan are well known. Generally,chitin is milled into a powder and demineralized with an organic acidsuch as acetic acid. Proteins and lipids are then removed by treatmentwith a base, such as sodium hydroxide, followed by chitin deacetylationby treatment with concentrated base, such as 40 percent sodiumhydroxide. The chitosan formed is washed with water until the desired pHis reached.

[0038] The properties of the aminopolyssaccharides, especially chitosan,relate to their polyelectrolyte and polymeric carbohydrate character.Thus, chitosan is generally insoluble in water, in alkaline solutions atpH levels above about 6.5, or in organic solvents. It generallydissolves readily in dilute solutions of organic acids such as formic,acetic, tartaric, glycolic, lactic and citric acids, and also in dilutemineral acids, except, for example, sulfuric acid. In general, theamount of acid required to dissolve chitosan is approximatelystoichiometric with the amino groups. Since the pKa for the amino groupspresent in chitosan material is between 6.0 and 7.0, they can beprotonated in very dilute acids or even close to neutral conditions,rendering a cationic nature to this biopolymer. This cationic nature isthe basis of many of the benefits of the chitosan material. Moregenerally, the cationic polysaccharides, like chitosan materials, can beconsidered as a linear polyelectrolyte with a high charge density whichcan interact with negatively charged surfaces, like proteins (e.g., byinterfering with the negatively charged wall construction ofmicroorganisms and/or enzymes, thereby acting as an antimicrobial agentand/or by reacting with the proteins present in bodily fluid, likemenses, thereby acting as a gelifying agent for such fluid) or likeanionic absorbent gelling materials that might be present in thearticles herein as an optional ingredient (e.g., in a preferredembodiment of the present invention, thereby further enhancing the odorcontrol properties of the cationic polysaccharides and providingoutstanding absorption properties even in presence ofelectrolyte-containing solutions).

[0039] Preferred chitosan materials for use herein have an averagedegree of deacetylation (D.A.) of more than 75%, preferably from 80% toabout 100%, even more preferably from 90% to 100% and most preferablyfrom 95% to about 100%. The degree of deacetylation refers to thepercentage of the amine groups that are deacetylated. Thischaracteristic is directly related to the hydrogen bonding existing inthis biopolymer, affecting its structure, solubility and ultimately itsreactivity. The degree of deacetylation can be determined by titration,dye adsorption, UV-VIS, IR, and NMR spectroscopy.

[0040] The degree of deacetylation will influence the cationicproperties of chitosan materials. By increasing the degree ofdeacetylation the cationic character of chitosan materials will increaseand thus their antimicrobial properties, absorbing ability and gelifyingability.

[0041] Suitable chitosan materials to use herein include bothwater-soluble and water insoluble chitosan. As used herein, a materialwill be considered to be water-soluble when it substantially dissolvesin excess water to form a clear and stable solution, thereby, losing itsinitially particulate form and becoming essentially molecularlydispersed throughout the water solution. Particularly suitable chitosanmaterials for use herein are water soluble, i.e., at least 0.5 gram,preferably at least 1 gram and most preferably at least 2 grams of thechitosan materials are soluble in 100 grams of water at 25° C. and oneatmosphere. By “solubility” of a given compound it is to be understoodherein the amount of said compound solubilised in de-ionized water at25° C. and one atmosphere in absence of precipitate.

[0042] As a general rule, the water-soluble chitosan materials will befree from a substantial degree of crosslinking, as crosslinking tends torender the chitosan materials water insoluble.

[0043] Water-soluble chitosan materials as defined herein have thebenefit to be more active in terms of odor control towards most of themalodorous compounds, present and soluble in the bodily fluid. Indeedsuch water-soluble chitosan materials have the ability to absorb and/orelectrostatically interfere with water-soluble malodorous componentslike short chain acid (e.g., butyric acid) or low molecular weightalcohol (e.g., ethanol).

[0044] Chitosan materials (i.e., chitosan and -chitosan salts, modifiedchitosans and cross-linked chitosans) may generally have a wide range ofmolecular weights. Chitosan materials with a wide range of molecularweights are suitable for use in the present invention, typicallychitosan materials for use herein have a molecular weight ranging from 1000 to 10 000 000 grams per gram moles and more preferably from 2 000 to1 000 000. Molecular weight means weight average molecular weight.Methods for determining the weight average molecular weight of chitosanmaterials are known to those skilled in the art. Typical methods includefor example light scattering, intrinsic viscosity and gel permeationchromatography. It is generally most convenient to express the molecularweight of a chitosan material in terms of its viscosity in a 1.0 weightpercent aqueous solution at 25° C. with a Brookfield viscometer. It iscommon to indirectly measure the viscosity of the chitosan material bymeasuring the viscosity of a corresponding chitosan salt, such as byusing a 1.0 weight percent acetic acid aqueous solution. Chitosanmaterials suitable for use in the present invention will suitably have aviscosity in a 1.0 weight percent aqueous solution at 25° C. of fromabout 1 mPa·s (I centipoise) to about 80,000 mPa·s (80,000 centipoise),more suitably from about 30 mPa·s (30 centipoise) to about 10,000 mPa·s(10,000 centipoise), even more suitably from 50 mPa·s (50 centipoise) toabout 1,000 mPa·s (1,000 centipoise) and most suitably from 100 mPa·s(100 centipoise) to about 500 mPa·s (500 centipoise).

[0045] Chitosan materials pH depends on the preparation of the chitosanmaterials. Preferred chitosan materials for use herein have an acidicpH, typically in the range of 4 to 6, more preferably from 4 to 5.5 andeven more preferably from 4.5 to 5.5. Highly preferred pH is around pH5, which corresponds to the skin pH. By pH of chitosan material it ismeant herein the pH of a 1% chitosan solution (1 gram of chitosanmaterial dissolved in 100 grams of distilled water) measured bypH-meter.

[0046] The cationic properties of the chitosan materials and thus theirantimicrobial, absorbing ability and gelifying ability increase withtheir acidic character. However too high acidity is detrimental to skinsafety. Thus it is highly preferred herein to use chitosan materialswith a pH in the range of 4.5 to 5.5, thereby delivering the bestcompromise between odor control and fluid handling properties on oneside and skin compatibility on the other side.

[0047] Particularly suitable aminopolysaccharides for use herein includeaminopolysaccharide salts, especially chitosan salts. A variety of acidscan be used for forming aminopolysaccharide salts like chitosan salts.Suitable acids for use are soluble in water or partially soluble inwater, are sufficiently acidic to form the ammonium salt of theaminopolysaccharide and yet not sufficiently acidic to cause hydrolysisof the aminopolysaccharide, and are present in amount sufficient toprotonate the reactive sites of the deacetylated aminopolysaccharide.

[0048] Preferred acids can be represented by the formula:

R—(COOH)_(n)

[0049] wherein n has a value of 1 or 2 or 3 and R represents a mono- ordivalent organic radical composed of carbon, hydrogen and optionally atleast one of oxygen, nitrogen and sulfur or R is simply a hydroxylgroup. Preferred acids are the mono- and dicarboxylic acids composed ofcarbon, hydrogen, oxygen and nitrogen (also called herein after aminoacids). Such acids are highly desired herein as they are biologicallyacceptable for use against or in proximity to the human body.Illustrative acids, in addition to those previously mentioned include,among others, citric acid, formic acid, acetic acid, N-acetylglycine,acetylsalicylic acid, fumaric acid, glycolic acid, iminodiacetic acid,itaconic acid, lactic acid, maleic acid, malic acid, nicotinic acid,2-pyrrolidone-5-carboylic acid, salicylic acid, succinamic acid,succinic acid, ascorbic acid, aspartic acid, glutamic acid, glutaricacid, malonic acid, pyruvic acid, sulfonyldiacetic acid, benzoic acid,epoxysuccinic acid, adipic acid, thiodiacetic acid and thioglycolicacid. Any aminopolysaccharide salts, especially chitosan salts formedfrom the reaction of the aminopolysaccharide with any of these acids aresuitable for use herein.

[0050] Examples of chitosan salts formed with an inorganic acid include,but are not limited to, chitosan hydrochloride, chitosan hydrobromide,chitosan phosphate, chitosan sulphonate, chitosan chlorosulphonate,chitosan chloroacetate and mixtures thereof. Examples of chitosan saltsformed with an organic acid include, but are not limited to, chitosanformate, chitosan acetate, chitosan lactate, chitosan glycolate,chitosan malonate, chitosan epoxysuccinate, chitosan benzoate, chitosanadipate, chitosan citrate, chitosan salicylate, chitosan propionate,chitosan nitrilotriacetate, chitosan itaconate, chitosan hydroxyacetate,chitosan butyrate, chitosan isobutyrate, chitosan acrylate, and mixturesthereof. It is also suitable to form a chitosan salt using a mixture ofacids including, for example, both inorganic and organic acids.

[0051] Preferred aminopolysaccharide salts, and especially chitosansalts for use herein are those formed by the reaction ofaminopolysaccharides with an amino acid. Amino acids are moleculescontaining both an acidic and amino functional group. The use of aminoacids is highly preferred as those aminopolysaccharide amino salts havehigher skin compatibility. Indeed most of the amino acids are naturallypresent on the skin and thus are non-irritating. Chitosan salts ofpyrrolidone carboxylic acid are effective moisturizing agents and arenon-irritating to skin. Such chitosan materials are suitable in case ofaccidental low rewetting occurrence and/or misuse of the articles.

[0052] Amino acids for use herein include both linear and/or cyclo aminoacids. Examples of amino acids for use herein include, but are notlimited to, alanine, valine, leucine, isoleucine, prolinephenylalanine,triptofane, metionine, glycine, serine, cysteine, tyrosine, asparagine,glutamine, aspartic acid, glutamic acid, lysine, arginine, istydine,hydroxyproline and the like. A particularly suitable example of cycloamino acid is pyrrolidone carboxylic acid, which is a carboxylic acid ofpyrrolidin-2-one as per following formula:

[0053] Highly preferred chitosan salts are chitosan pyroglutamate salt,which is a mixture of chitosan (a macromolecule) and pyroglutamic acid(independent monomers), chitosonium pyrrolidone carboxylate, which isthe chitosan salt of 2-pyrrolidone-5-carboxylic acid.

[0054] Reference is made to WO 98/07618, which describes in detailsprocesses for the preparation of such aminopolysaccharide salts.

[0055] Other aminopolysaccharide materials suitable for use hereininclude cross-linked aminopolysaccharides and modifiedaminopolysaccharides, especially cross-linked chitosans and modifiedchitosans.

[0056] Suitable crosslinking agents for use herein are organic compoundshaving at least two functional groups or functionalities capable ofreacting with active groups located on the aminopolysaccharide,typically chitosan materials. Examples of such active groups include,but are not limited to, carboxylic acid (—COOH), or hydroxyl (—OH)groups. Examples of such suitable crosslinking agents include, but arenot limited to, diamines, polyamines, diols, polyols, dicarboxylicacids, polycarboxylic acids, aminocarboxylic acids, aminopolycarboxylicacids polyoxides and the like. One way to introduce a crosslinking agentwith the chitosan solution is to mix the crosslinking agent withchitosan during preparation of the solution. Another suitablecrosslinking agent comprises a metal ion with more than two positivecharges, such as Ca²⁺, Al³⁺, Fe³⁺, Ce³⁺, Ce⁴⁺, Ti⁴⁺, Zr⁴⁺, and Cr³⁺.Since the cations on chitosan possess antimicrobial properties, it ispreferred herein to not use a crosslinking agent reacting to thecations, unless no alternative crosslinking agent is available.

[0057] In the embodiment herein where crosslinking agents are used, asuitable amount of crosslinking agent is from 0.001 to 30 weight percentbased on the total dry weight of chitosan used to prepare thecrosslinked-chitosan, more specifically from 0.02 to 20 weight percent,more specifically from 0.05 to 10 weight percent and most preferablyfrom 0.1 to 5 weight percent.

[0058] Modified chitosans or chitins for use herein are any chitosan orchitin where the glucan chains carry pendant groups. Examples of suchmodified chitosans include carboxymethyl chitosan, methyl pyrrolidinonechitosan, glycol chitosan and the like. Methyl pyrrolidone chitosan isfor instance described in U.S. Pat. No. 5,378,472, incorporated hereinby reference. Water-soluble glycol chitosan and carboxymethyl chitosanare for instance described in WO 87/07618, incorporated herein byreference Particularly suitable modified chitosans for use hereininclude water-soluble covalently bonded chitosan derivatives orionically bonded chitosan derivatives obtained by contacting salt ofchitosan with electrophilic organic reagents. Such water-solublechitosan derivatives are described in EP-A737 692, which is hereinincorporated by reference.

[0059] Suitable electrophilic organic reagents suitable for use for thepreparation of chitosan derivatives contain from 2 to 18 carbon atoms ormore per molecule and typically from 2 to 10 carbon atoms per molecule.In addition the electrophilic organic reagents contain groups, which arereactive, i.e. capable of forming a covalent bond with a nucleophile.Typical electrophilic organic reagents include, for example, ethyleneoxide, propylene oxide, butylene oxide, glycidol,3-chloro-1,2-propanediol, methyl chloride, ethyl chloride, isatoicanhydride, succinic anhydride, octenylsuccinic anhydride, aceticanhydride, gamma-butyrolactone, b-propiolactone, 1,3-propanesultone,acrylamide, glycidyltrimethyl ammonium chloride, glycidyldimethylalkylammonium chloride such as lauryl, sodium chlorosulfonate, dimethylsulfate, sodium chloroethanesulfonate, monochloroacetic acid, alkylphenyl glycidyl ethers, glycidyl trimethoxysilanes, 1,2-epoxy dodecane.One preferred class of electrophilic organic reagent includes thoseelectrophilic organic reagents, which contain an epoxide group, at leastone acid group, preferably a diacid group and have from 3 to 18,preferably from 3 to 6 carbon atoms per molecule. Other preferredelectrophilic organic reagents include cis-electrophilic organicreagents and trans-electrophilic organic reagent, with cis-electrophilicorganic reagents being especially preferred. The electrophilic organicreagent may react with either the free amine or the underivatizedhydroxyl groups of the chitosan. It is known that the aminefunctionality of the chitosan is generally regarded as a strongernucleophilic site than the hydroxyl groups. Consequently weakerelectrophiles will tend to react more readily with the amine groups thanwith the hydroxyl groups of the chitosan.

[0060] Preferably an effective amount of electrophilic organic reagentis substituted onto the chitosan to achieve the desired properties ofthe chitosan derivative, namely its water-soluble properties. Typicallythe chitosan derivatives suitable for use herein (modified chitosan)have a MS of from 0.03 to 10 moles of the electrophilic organic reagentper mole of glucosamine monomer unit. The term molar substitution (MS),means the moles of electrophilic organic reagent substituted on thechitosan per mole of glucosamine monomer unit.

[0061] In addition further modified chitosan can be prepared whichcontain other substituent groups, such as hydroxalkyl ether group (e.g.,hydroxyethyl or hydroxypropyl ether groups), carboxyalkyl ether groups(e.g., carboxymethyl group), amide groups (e.g., succinyl groups), estergroups (e.g., acetate groups) or amino groups (e.g.,3-(trimethylammonium chloride)-2-hydroxylpropyl or3-(dimethyloctadecylammonium chloride)-2-hydroxpropyl ether groups) inaddition to the electrophilic organic reagent groups. These othersubstituent groups may be introduced prior to or subsequent to thereaction with the electrophilic organic reagent, or introducedsimultaneously by reaction of the chitosan salt with the electrophilicorganic reagent and the other derivatizing reagent.

[0062] Typically such covalently bonded chitosan derivative might beobtainable by a process which includes the step of (a) dispersing a saltof chitosan (e.g., any one of those described herein before) in aneffective amount of an aqueous caustic medium to form a neutralizedchitosan containing free amine groups, (b) introducing an electrophilicorganic reagent in the slurry and (c) maintaining the slurry at atemperature and time effective to promote the substitution of theelectrophilic organic reagent onto the chitosan to form a covalentlybonded chitosan derivative and the dissolution of the covalently bondedchitosan into the aqueous medium. The chitosan derivatives can beprepared in either salt form, i.e., ionically bonded, or in thecovalently bonded form. Processes for the preparation of such chitosanderivatives are described in depth in EP-A-737 692, incorporated hereinby reference.

[0063] Suitable chitosans are commercially available from numerousvendors. Exemplary of a commercially available chitosan materials arethose available from for example the Vanson Company. The preferredchitosan salt for use herein is chitosan pyrrolidone carboxylate (alsocalled chitosonium pyrrolidone carboxylate), which has a degree ofdeacetylation more than 85%, a water solubility of 1% (1 gram is solublein 100 grams of distilled water at 25° C. and one atmosphere), a pH of4.5 and a viscosity between 100-300 cps. Chitosan pyrrolidonecarboxylate is commercially available under the name Kytamer® PC fromAmerchol Corporation.

[0064] Typically, the articles like disposable absorbent articlescomprise the cationic polysaccharide or a mixture thereof at a level offrom 0.5 gm-2 to 500 gm⁻², preferably from 1 to 200 gm⁻², morepreferably from 3 gm⁻² to 100 gm⁻² and most preferably from 4 gm⁻² to 50gm⁻²

The Odor Controlling Agents

[0065] The articles according to the present invention further compriseon top of the cationic polysaccharide or mixture thereof describedherein before, at least one additional odor-controlling agent or amixture thereof.

[0066] Typically, the articles like disposable absorbent articles hereincomprise from 1 to 600 gm⁻², more preferably from 5 to 400 gm⁻², mostpreferably from 10 to 200 gm⁻², of the odor controlling agent or amixture thereof.

[0067] Suitable odor controlling agents for use herein include odorabsorbent agents known to those skilled in the art, namely activatedcarbons, clays, zeolites, kieselguhr, diatomaceous earth, starches,cyclodextrin, ion exchange resins and the like. Preferred herein arezeolites and/or cyclodextrin. Other suitable odor controlling agents foruse herein include chelating agents or a mixture thereof. The articlesherein may contain mixtures of odor absorbent agents with chelatingagents. The present invention is based on the finding that the cationicpolysaccharides, especially chitosan materials, together with an odorcontrolling agent, preferably an odor absorbent agent (preferablyzeolite and/or cyclodextrin) and/or a chelating agent (preferablyethylene diamine tetra acetates) deliver a synergistic odor controlbenefit towards malodors associated with bodily fluids, especiallymenses.

[0068] It is speculated that the cationic polysaccharides herein preventthe formation of malodorous compounds, typically by reducing or eveninhibiting the microbial and enzymatic development in bodily fluid,thereby reducing the total amount of malodorous compounds associatedwith bodily fluid. This results in more effective use of odor absorbentagents over prolonged period of time before the saturation of the activecenter of absorption of such agents. Advantageously these odor absorbentagents, like zeolite or cyclodextrine or derivatives thereof, controlodor associated with bodily fluids/exudates not only by absorbingmalodorous components present in the bodily fluids coming into contacttherewith, typically in the absorbent article, but also by absorbing thevolatile malodorous components present in the headspace of the absorbentarticle which would otherwise not have been controlled in presence ofthe cationic polysaccharides used alone as the sole odor controllingagent in the absorbent article.

[0069] In a preferred embodiment herein the cationic polysaccharide andthe odor absorbent agent are present in weight ratio from the cationicpolysaccharide to the odor absorbent agent of from 1:10 to 10:1,preferably from 1:5 to 5:1 and more preferably at a ratio around 1:1.Indeed it is within these ratios ranges that optimum odor controlproperties are obtained versus bodily fluids.

Zeolite

[0070] A particularly suitable odor absorbent agent herein is zeolite.The use and manufacture of zeolite material is well know in theliterature and is described in the following reference texts: ZEOLITESYNTHESIS, ACS Symposium Series 398, Eds. M. L. Occelli and H. E Robson(1989) pages 2-7; ZEOLITE MOLECULAR SIEVES, Structure, Chemistry andUse, by D. W. Breck, John Wiley and Sons (1974) pages 245-250, 313-314and 348-352; MODERN APPLICATIONS OF MOLECULAR SIEVE ZEOLITES, Ph.D.Dissertation of S. M. Kuznicki, U. of Utah (1980), available fromUniversity of Microfilms International, Ann Arbor, Mich., pages 2-8.

[0071] Zeolites are crystalline aluminosilicates of group IA and groupIIA elements such as Na, K, Mg, and Ca are chemically represented by theempirical formula:

M_(2/n)O.Al₂O₃ .ySiO₂ . wH₂O

[0072] where y is 2 or greater, n is the cation valence, and w is thewater content in the voids of the zeolite.

[0073] Structurally, zeolites are complex, crystalline inorganicpolymers based on an infinitely extending framework of AlO₄ and SiO₄tetrahedra linked to each other by sharing of oxygen ions. Thisframework structure contains channels or interconnected voids that areoccupied by the cations and water molecules.

[0074] The structural formula of a zeolite is based on the crystal unitcell, the smallest unit of structure, represented by

M_(x/n)[(AlO₂)_(x)(SiO₂)_(y) ].wH₂O

[0075] where n is the valence of cation M, w is the number of watermolecules per unit cell, x and y are the total number of tetrahedra perunit cell, y/x usually having values of 1-5.

[0076] Zeolites may be naturally derived or synthetically manufactured.The synthetic zeolites being preferred for use herein. Suitable zeolitesfor use herein include zeolite A, zeolite P, zeolite Y, zeolite X,zeolite DAY, zeolite ZSM-5, or mixtures thereof. Most preferred iszeolite A.

[0077] According to the present invention the zeolite is preferablyhydrophobic. This is typically achieved by increasing the molar ratio ofthe SiO₂ to A102 content such that the ratio of x to y is at least 1,preferably from 1 to 500, most preferably from 1 to 6.

[0078] According to the present invention the articles typicallycomprise from 0 to 300 gm⁻², more preferably from 40 to 250 gm⁻² mostpreferably from 60 to 200 gm⁻², of zeolite based on 100% purity or amixture thereof.

Cyclodextrin and Derivatives Thereof

[0079] A particularly suitable odor absorbent agent for use herein iscyclodextrin or a derivative thereof or a mixture thereof. Thesematerials are preferred herein due to their dual function ofsolubilising cationic polysaccharides, typically those that are partlywater soluble or non water-soluble and of their own ability to absorbodor.

[0080] Cyclodextrin or a derivative thereof may thus act as a carrierfor the cationic polysaccharides, typically chitosan materials, and thuscontribute to bring chitosan materials, especially those being partlywater soluble or non soluble (i.e., typically having a solubility inwater of less than 0.5 gram per 100 grams of distilled water at 25° C.and one atmosphere), into closer contact with the liquid bodily fluidand thus the water soluble malodorous components resulting from thedegradation of lipids, proteins and/or sugars like amine, butyric acidand the like. It is speculated that cyclodextrin or derivatives thereofhelp to further solubilise the cationic polysaccharides and this resultsin significantly improved overall odor control (synergistic effect).

[0081] The unique shape and physical-chemical property of the cavityenable the cyclodextrin molecules to absorb (form inclusion complexeswith) organic molecules or parts of organic molecules, which can fitinto the cavity.

[0082] As used herein, the term “cyclodextrin” includes any of the knowncyclodextrins such as unsubstituted cyclodextrins containing from six totwelve glucose units, especially, alpha-cyclodextrin, beta-cyclodextrin,gamma-cyclodextrin and/or their derivatives and/or mixtures thereof. Thealpha-cyclodextrin consists of six glucose units, the beta-cyclodextrinconsists of seven glucose units, and the gamma-cyclodextrin consists ofeight glucose units arranged in a donut-shaped ring. The specificcoupling and conformation of the glucose units give the cyclodextrins arigid, conical molecular structure with a hollow interior of a specificvolume. The “lining” of the internal cavity is formed by hydrogen atomsand glycosidic bridging oxygen atoms; therefore this surface is fairlyhydrophobic. Non-derivatised (normal) beta-cyclodextrin can be usedherein.

[0083] Particularly preferred cyclodextrins useful in the presentinvention are highly water-soluble such as, alpha-cyclodextrin andderivatives thereof, gamma-cyclodextrin and derivatives thereof,derivatised beta-cyclodextrins, and/or mixtures thereof.

[0084] The derivatives of cyclodextrin consist mainly of moleculeswherein some of the OH groups are converted to OR groups. Cyclodextrinderivatives include, e.g., those with short chain alkyl groups such asmethylated cyclodextrins, and ethylated cyclodextrins, wherein R is amethyl or an ethyl group; those with hydroxyalkyl substituted groups,such as hydroxypropyl cyclodextrins and/or hydroxyethyl cyclodextrins,wherein R is a —CH₂—CH(OH)—CH₃ or a —CH₂CH₂—OH group; branchedcyclodextrins such as maltose-bonded cyclodextrins; cationiccyclodextrins such as those containing 2-hydroxy-3(dimethylamino)propylether, wherein R is CH₂—CH(OH)—CH₂—N(CH₃)₂ which is cationic at low pH;quatemary ammonium, e.g., 2-hydroxy-3-(trimethylammonio)propyl etherchloride groups, wherein R is CH₂—CH(OH)—CH₂—N⁺(CH₃)₃Cl—; anioniccyclodextrins such as carboxymethyl cyclodextrins, cyclodextrinsulfates, and cyclodextrin succinylates; amphoteric cyclodextrins suchas carboxymethyl/quatemary ammonium cyclodextrins; cyclodextrins whereinat least one glucopyranose unit has a 3-6-anhydro-cyclomalto structure,e.g., the mono-3-6-anhydrocyclodextrins, as disclosed in “OptimalPerformances with Minimal Chemical Modification of Cyclodextrins”, F.Diedaini-Pilard and B. Perly, The 7th International CyclodextrinSymposium Abstracts, April 1994, p. 49, herein incorporated byreference; and mixtures thereof. Other cyclodextrin derivatives aredisclosed in U.S. Pat. No. 3,426,011, Parmerter et al., issued Feb. 4,1969; U.S. Pat. Nos. 3,453,257; 3,453,258; 3,453,259; and 3,453,260, allin the names of Parmerter et al., and all issued Jul. 1, 1969;3,459,731, Gramera et al., issued Aug. 5, 1969; U.S. Pat. No. 3,553,191,Parmerter et al., issued Jan. 5, 1971; U.S. Pat. No. 3,565,887,Parmerter et al., issued Feb. 23, 1971; U.S. Pat. No. 4,535,152, Szejtliet al., issued Aug. 13, 1985; U.S. Pat. No. 4,616,008, Hirai et al.,issued Oct. 7, 1986; U.S. Pat. No. 4,678,598, Ogino et al., issued Jul.7, 1987; U.S. Pat. No. 4,638,058, Brandt et al., issued Jan. 20, 1987;and U.S. Pat. No. 4,746,734, Tsuchiyama et al., issued May 24, 1988; allof said patents being incorporated herein by reference.

[0085] Highly water-soluble cyclodextrins are those having watersolubility of at least about 10 g in 100 ml of water at roomtemperature, preferably at least about 20 g in 100 ml of water, morepreferably at least about 25 g in 100 ml of water at room temperature.These are easy to use, but are typically more expensive than thenon-derivatised beta-cyclodextrin. Examples of preferred water-solublecyclodextrin derivatives suitable for use herein are hydroxypropylalpha-cyclodextrin, methylated alpha-cyclodextrin, methylatedbeta-cyclodextrin, hydroxyethyl beta-cyclodextrin, and hydroxypropylbeta-cyclodextrin. Hydroxyalkyl cyclodextrin derivatives preferably havea degree of substitution of from about 1 to about 14, more preferablyfrom about 1.5 to about 7, wherein the total number of OR groups percyclodextrin is defined as the degree of substitution. Methylatedcyclodextrin derivatives typically have a degree of substitution of fromabout 1 to about 18, preferably from about 3 to about 16. A knownmethylated beta-cyclodextrin is heptakis-2,6-di-O-methyl-β-cyclodextrin,commonly known as DIMEB, in which each glucose unit has about 2 methylgroups with a degree of substitution of about 14. A preferred, morecommercially available methylated beta-cyclodextrin is a randomlymethylated beta-cyclodextrin having a degree of substitution of about12.6. The preferred cyclodextrins are available, e.g., from CerestarUSA, Inc. and Wacker Chemicals (USA), Inc.

[0086] It can be desirable to use a mixture of cyclodextrins. Suchmixtures can complex with a wider range of odor molecules having a widerrange of molecular sizes. Preferably at least a portion of such amixture of cyclodextrins is alpha-cyclodextrin or its derivatives,gamma-cyclodextrin or its derivatives thereof, and/or beta-cyclodextrinor its derivatives.

[0087] According to the present invention the articles typicallycomprise from 0 to 300 gm⁻², more preferably from 5 to 250 gm⁻² mostpreferably from 7 to 200 gm-2, of cyclodextrin or derivative thereof ormixture thereof.

Chelating Agents

[0088] Suitable chelating agents for use herein are those known to thoseskilled in the art. Suitable chelating agents include for examplephosphonate chelating agents, polyfunctionally-substituted aromaticchelating agents, amino carboxylate chelating agents, other chelatingagents like ethylene diamine N,N′-disuccinic acid, aspartic acid,glutamic acid, malonic acid, glycine and mixtures thereof.

[0089] Suitable phosphonate chelating agents to be used herein mayinclude ethydronic acid, alkali metal ethane 1-hydroxy diphosphonates aswell as amino phosphonate compounds, including amino alkylene poly(alkylene phosphonate), alkali metal ethane 1-hydroxy diphosphonates,nitrilo trimethylene phosphonates, ethylene diamine tetra methylenephosphonates, aminotri(methylene phosphonates) (ATMP) and diethylenetriamine penta methylene phosphonates. The phosphonate compounds may bepresent either in their acid form or as salts of different cations onsome or all of their acid functionalities. Typically, these aminophosphonates do not contain alkyl or alkenyl groups with more than 6carbon atoms. Preferred phosphonate chelating agents to be used hereinare diethylene triamine penta methylene phosphonates (DETPMP). Suchphosphonate chelating agents are commercially available from Monsantounder the trade name DEQUEST®.

[0090] Polyfunctionally-substituted aromatic chelating agents may alsobe useful in the compositions herein. See U.S. Pat. No. 3,812,044,issued May 21, 1974, to Connor et al. Preferred compounds of this typein acid form are dihydroxydisulfobenzenes such as1,2-dihydroxy-3,5-disulfobenzene.

[0091] A preferred biodegradable chelating agent for use herein isethylene diamine N,N′-disuccinic acid, or alkali metal, or alkalineearth, ammonium or substitutes ammonium salts thereof or mixturesthereof. Ethylenediamine N,N′-disuccinic acids, especially the (S,S)isomer have been extensively described in U.S. Pat. No. 4,704,233, Nov.3, 1987. to Hartman and Perkins. Ethylenediamine N,N′-disuccinic acidsis, for instance, commercially available under the trade name ssEDDS®from Palmer Research Laboratories.

[0092] Suitable amino carboxylate chelating agents to be used hereininclude ethylene diamine tetra acetates (EDTA), diethylene triaminepentaacetates, diethylene triamine pentaacetate (DTPA),N-hydroxyethylethylenediamine triacetates, nitrilotri-acetates,ethylenediamine tetrapropionates, triethylenetetraaminehexa-acetates,diethylenetriamine pentaacetates, ethanol-diglycines, propylene diaminetetracetic acid (PDTA) and methyl glycine di-acetic acid (MGDA), both intheir acid form, or in their alkali metal, ammonium, and substitutedammonium salt forms. Particularly suitable amino carboxylates to be usedherein are ethylene diamine tetra acetates (EDTA), diethylene triaminepenta acetic acid (DTPA) or mixture thereof.

[0093] The more preferred chelating agents for use herein are selectedfrom ethylenediamine tetracetate, -triacetate, -diacetate, and-monoacetate, ethylenediamine N,N,-disuccinic acid (sodium salt),ethylenediamine penta (methylene phosphonic acid) (sodium salt),ethylenediamine tetra (methylene phosphonic acid) or mixtures thereof.Most preferably the chelating agent is ethylene diamine tetracetate.

[0094] According to the present invention the articles typicallycomprise from 0 to 300 gm⁻², more preferably from 5 to 250 gm⁻² mostpreferably from 7 to 200 gm⁻², of chelating agent or mixture thereof.

[0095] It is speculated that the chelating agents herein participate tothe antimicrobial activities of the cationic polysaccharides herein.Indeed they chelate positively charged nutriments for microorganismslike growth factors (e.g., calcium, magnesium and/or potassium) that arevital for any microbial development, thereby reducing such development.They thus supplement the antimicrobial direct activity of the cationicpolysaccharides herein, especially chitosan materials. This is even morethe case in the preferred embodiments of the present invention, wherechitosan materials with high degree of deacetylation are used (more than75%) as defined herein, and where as a consequence such chitosanmaterials are not able to act as chelating agents towards positivelycharged nutriments.

[0096] In a preferred embodiment herein the cationic polysaccharide andthe chelating agent are present in weight ratio from the cationicpolysaccharide to the chelating agent of from 1:10 to 10:1, preferablyfrom 1:5 to 5:1 and more preferably from 1:3 to 3:1. Indeed it is withinthese ratios ranges that optimum odor control properties are obtainedversus bodily fluids.

Optional Agents

[0097] The articles according to the present invention may furthercomprise other conventional agents like absorbent gelling materials.

Absorbent Gelling Materials

[0098] As is well known from recent commercial practice, absorbentgelling materials (sometimes referred to as “super-sorbers”) arebecoming broadly used in absorbent articles. AGMs are materials, whichhave the twofold property of absorbing and retaining fluids and odors,and thus further contribute to the benefit of the present invention.

[0099] Particularly preferred absorbent gelling materials for use hereinare anionic absorbent gelling materials, i.e., absorbent gellingmaterials that are predominantly negatively charged. These absorbentgelling materials can be any material having superabsorbent propertiesin which the functional groups are anionic, namely sulphonic groups,sulphate groups, phosphate groups or carboxyl groups. Preferably thefunctional groups are carboxyl groups. Particularly preferred anionicabsorbent gelling materials for use herein are synthetic anionicabsorbent gelling materials. Synthetic anionic absorbent gellingmaterials are preferred herein as they deliver higher odor and fluidabsorption performance, this even under pressure, as compared to theabsorption performance associated with natural anionic absorbent gellingmaterials like anionic polysaccharides when used in the same absorbentarticle.

[0100] Generally the functional groups are attached to a slightlycross-linked acrylic base polymer. For example the base polymer may be apolyacrylamide, polyvinyl alcohol, ethylene maleic anhydride copolymer,polyvinylether, polyvinyl sulphonic acid, polyacrylic acid,polyvinylpyrrolidone and polyvinylmorpholine. Copolymers of thesemonomers can also be used. Particular base polymers include cross-linkedpolyacrylates, hydrolyzed acrylonitrile grafted starch, starchpolyacrylates and isobutylene maleic anhydride copolymers.

[0101] Such materials form hydrogels on contact with water (e.g., withurine, blood, and the like). One highly preferred type ofhydrogel-forming, absorbent gelling material is based on polyacids,especially polyacrylic acid. Hydrogel-forming polymeric materials ofthis type are those, which, upon contact with fluids (i.e., liquids)such as water or body fluids, imbibe such fluids and thereby formhydrogels. These preferred absorbent gelling materials will generallycomprise substantially water-insoluble, slightly cross-linked, partiallyneutralized, hydrogel-forming polymer materials prepared frompolymerisable, unsaturated, acid-containing monomers. In such materials,the polymeric component formed from unsaturated, acid-containingmonomers may comprise the entire gelling agent or may be grafted ontoother types of polymer moieties such as starch or cellulose. Acrylicacid grafted starch materials are of this latter type. Thus, thepreferred absorbent gelling materials include hydrolyzed acrylonitrilegrafted starch, acrylic acid grafted starch, polyacrylates, maleicanhydride-based copolymers and combinations thereof. Especiallypreferred absorbent gelling materials are the polyacrylates and acrylicacid grafted starch.

[0102] Whatever the nature of the polymer components of the preferredabsorbent gelling materials, such materials will in general be slightlycross-linked. Crosslinking serves to render these preferredhydrogel-forming absorbent materials substantially water-insoluble, andcross-linking also in part determines the gel volume and extractablepolymer characteristics of the hydrogels formed there from. Suitablecross-linking agents are well known in the art and include, for example,(1) compounds having at least two polymerisable double bonds; (2)compounds having at least one polymerisable double bond and at least onefunctional group reactive with the acid-containing monomer material; (3)compounds having at least two functional groups reactive with theacid-containing monomer materials; and (4) polyvalent metal compoundswhich can from ionic cross-linkages. Cross-linking agents of theforegoing types are described in greater detail in Masuda et al; U.S.Pat. No. 4,076,663; Issued Feb. 28, 1978. Preferred cross-linking agentsare the di- or polyesters of unsaturated mono-or polycarboxylic acidswith polyols, the bisacrylamides and the di-or triallyl amines.Especially preferred cross-linking agents areN,N′-methylenebisacrylamide, trimethylol propane triacrylate andtriallyl amine. The cross-linking agent will generally comprise fromabout 0.001 mole percent to 5 mole percent of the preferred materials.More preferably, the cross-linking agent will comprise from about 0.01mole percent to 3 mole percent of the gelling materials used herein.

[0103] The preferred absorbent gelling materials used herein are thosewhich have a relatively high capacity for imbibing fluids encountered inthe absorbent articles; this capacity can be quantified by referencingthe “gel volume” of said absorbent gelling materials. Gel volume can bedefined in terms of the amount of synthetic urine absorbed by any givenabsorbent gelling agent buffer and is specified as grams of syntheticurine per gram of gelling agent.

[0104] Gel volume in synthetic urine (see Brandt, et al, below) can bedetermined by forming a suspension of about 0.1-0.2 parts of driedabsorbent gelling material to be tested with about 20 parts of syntheticurine. This suspension is maintained at ambient temperature under gentlestirring for about 1 hour so that swelling equilibrium is attained. Thegel volume (grams of synthetic urine per gram of absorbent gellingmaterial) is then calculated from the weight fraction of the gellingagent in the suspension and the ratio of the liquid volume excluded fromthe formed hydrogel to the total volume of the suspension. The preferredabsorbent gelling materials useful in this invention will have a gelvolume of from about 20 to 70 grams, more preferably from about 30 to 60grams, of synthetic urine per gram of absorbent gelling material.Another feature of the most highly preferred absorbent gelling materialsrelates to the level of extractable polymer material present in saidmaterials. Extractable polymer levels can be determined by contacting asample of preferred absorbent gelling material with a synthetic urinesolution for the substantial period of time (e.g., at least 16 hours)which is needed to reach extraction equilibrium, by then filtering theformed hydrogel from the supernatant liquid, and finally by thendetermining the polymer content of the filtrate. The particularprocedure used to determine extractable polymer content of the preferredabsorbent gelling agent buffers herein is set forth in Brandt, Goldmanand Inglin; U.S. Pat. No. 4,654,039; Issues Mar. 31, 1987, Reissue32,649, The absorbent gelling materials which are especially useful inthe absorbent articles herein are those which have an equilibriumextractable content in synthetic urine of no more than about 17%,preferably no more than about 10% by weight of the absorbent gellingmaterial.

[0105] The preferred, slightly cross-linked, hydrogel-forming absorbentgelling materials will generally be employed in their partiallyneutralized form. For purposes described herein, such materials areconsidered partially neutralized when at least 25 mole percent, andpreferably at least 50 mole percent of monomers used to form the polymerare acid group-containing monomers, which have been neutralized with asalt-forming cation. Suitable salt-forming cations include alkali metal,ammonium, substituted ammonium and amines. This percentage of the totalmonomers utilized, which are neutralized acid group-containing monomers,is referred to as the “degree of neutralization”. Typically, commercialabsorbent gelling materials have a degree of neutralization somewhatfrom 25% to 90%.

[0106] The absorbent gelling materials herein before described aretypically used in the form of discrete particles. Such absorbent gellingmaterials can be of any desired shape, e.g., spherical orsemi-spherical, cubic, rod-like polyhedral, etc. Shapes having a largegreatest dimension/smallest dimension ratio, like needles and flakes,are also contemplated for use herein. Agglomerates of absorbent gellingmaterial particles may also be used.

[0107] The size of the absorbent gelling material particles may varyover a wide range. For reason of industrial hygiene, average particlesizes smaller than about 30 microns are less desirable. Particles havinga smallest dimension larger than about 2 mm may also cause a feeling ofgrittiness in the absorbent article, which is undesirable from aconsumer aesthetics standpoint. Furthermore, rate of fluid absorptioncan be affected by particle size. Larger particles have very muchreduced rates of absorption. Preferred for use herein are absorbentgelling material s particles substantially all of which have a particlesize of from about 30 microns to about 2 mm.

[0108] “Particle Size” as used herein means the weighted average of thesmallest dimension of the individual particles. The amount of absorbentgelling material particles used in the article according to the presentinvention, especially disposable absorbent articles, will typicallyrange from 5 gm-2 to 250 gm⁻², preferably from 7 gm⁻² to 150 gm⁻², morepreferably from 10 gm⁻² to 100 gm⁻². Anionic absorbent gelling materialsare suitably used on top of the cationic polysaccharides and odorcontrolling agents herein as they further contribute to enhance thebenefices of the present invention. Indeed the anionic absorbent gellingmaterials enhance the cationic properties of the cationicpolysaccharides, thus their odor control properties. Without to be boundby any theory, it is believed that the negatively charged anionic groupsof the anionic absorbent gelling materials protonate the cationicpolysaccharides, thereby enhancing the cationic properties of forexample chitosan materials.

[0109] Advantageously the addition of anionic absorbent gellingmaterials, namely synthetic anionic absorbent gelling materials asdescribed herein (typically having a degree of neutralization of from25% to 90%) on top of cationic polysaccharides, especially chitosanmaterials, in an absorbent article results in outstanding fluidabsorption capacity not only towards water but especially towardselectrolytes-containing solutions like menses.

[0110] Furthermore the use of anionic absorbent gelling materials,namely synthetic anionic absorbent gelling materials as described herein(typically having a degree of neutralization of from 25% to 90%) on topof cationic polysaccharides, especially chitosan materials, in anabsorbent article, exhibit high gel strength during fluid absorption.Indeed this combination results in improved absorption capacity underload conditions, in decreased rewetting and wetting through and henceimproved comfort.

[0111] Advantageously the presence of anionic synthetic absorbentgelling agents on top of the odor control system of the presentinvention results in optimum fluid absorption and optimum odor controlof malodors typically associated with bodily fluids.

The Disposable Absorbent Article

[0112] The odor control system (i.e., at least a cationic polysaccharideand an odor controlling agent) as well as the optional absorbent gellingmaterial may be incorporated into the absorbent article by any of themethods disclosed in the art, for example layered on the core of theabsorbent article or mixed within the fibers of the absorbent core.

[0113] The cationic polysaccharide and the odor-controlling agent arepreferably incorporated between two layers of cellulose tissue.Optionally the system may be bonded between two cellulose tissue layerswith, for example, a hot melt adhesive or any suitable bonding system,as described in WO 94/01069.

[0114] In one embodiment of the present invention the cationicpolysaccharide and the odor controlling agent are incorporated in alayered structure in accordance with the disclosure of WO 94/01069 orItalian patent application number TO 93A 001028. TO 93A 001028 describesa layered structure substantially as described in WO 94/01069 with theexception that TO 93A 001028 comprises a much higher quantity ofabsorbent gelling material in the intermediate layer which is betweenthe fibrous layers (120gm⁻²) that would be incorporated as an optionalcomponent in the present invention. The intermediate layer comprises inparticular a polyethylene powder as thermoplastic material, which ismixed with the odor controlling agent and cationic polysaccharide. Themixture is then heated such that the polyethylene melts and glues thelaminate layers together. Adhesive lines are preferably also placed onthe edges of the laminate to ensure that the edges of the laminate stickand any loose cationic polysaccharide powder and odor controlling agentpowder present do not fall out of the laminate.

[0115] Alternatively, the polyethylene powder may be replaced by aconventional glue for instance those commercially available from ATOFindley under the name H20-31® to glue the laminate layers and/orcomponents together. Advantageously this method step allows to avoid theheating step necessary when using polyethylene powder.

[0116] The cationic polysaccharide and the odor controlling agent may bedistributed homogeneously or non homogeneously over the entire absorbentarticle or in at least one layer of the topsheet, or at least one layerof the backsheet or in at least one layer of the core or any mixturethereof. The cationic polysaccharide and the odor controlling agent maybe distributed homogeneously or non homogeneously on the whole surfaceof the desired layer or layers, or on one or several area of the surfacelayer/layers to which it is positioned (e.g. central area and/orsurrounding area like the edges of a layer of the absorbent article) ormixtures thereof.

[0117] The cationic polysaccharide and the odor-controlling agent may bepositioned together in the same location (e.g., layer) or separately indifferent locations/layers. For example in one embodiment herein theodor controlling agent (e.g., zeolite and/or cyclodextrin and/or EDTA)is positioned such that at least a portion of the fluid/exudate comesinto contact with it before the cationic polysaccharide, preferablychitosan material. Preferably the odor controlling agent is located inthe core towards the topsheet or located in the topsheet itself(preferably the secondary topsheet) and the cationic polysaccharide islocated further away from the topsheet than the odor controlling agent.In one embodiment of the present invention, the odor-controlling agentis positioned in at least one of the topsheet layers and the cationicpolysaccharide, typically chitosan material, is positioned in the core.In another embodiment herein the odor controlling agent and the cationicpolysaccharide are both located in the core, but the cationicpolysaccharide is located beneath the odor-controlling agent, typicallythe cationic polysaccharide is located towards the backsheet. In anotherembodiment the odor controlling agent is located in the absorbent coreand the cationic polysaccharide in the backsheet itself (preferably thesecondary backsheet).

[0118] In a preferred embodiment herein, wherein an absorbent gellingmaterial is present, the absorbent gelling material and the odorcontrolling agent are positioned such that at least a portion of thebodily fluid/exudate comes into contact with said absorbent gellingmaterial and odor controlling agent before the cationic polysaccharide.In a highly preferred embodiment herein the absorbent gelling materialand odor controlling agent are located in the absorbent core and thecationic polysaccharide, typically chitosan material, is located too inthe absorbent core but further away from the topsheet than the absorbentgelling material and odor controlling agent. In an execution wherein thecore is made of laminate of two layers of cellulose tissue, theabsorbent gelling material and the odor controlling agent areincorporated between these two layers and the polysaccharide is appliedon the layer positioned in proximity to the backsheet, preferably on theinner side of this layer so as to be in close proximity to the absorbentgelling material and odor controlling agent. Such executions areparticularly beneficial for combining optimum odor control propertieswith optimum fluid handling, i.e., optimum odor and fluid absorption andretention without any leakage through or rewetting occurrence. Thecationic properties of the cationic polysaccharides will be boosted dueto the close proximity to the absorbent gelling material. Furthermorethe cationic polysaccharide due to its gelifying properties will havethe tendency to form a so-called impermeable layer towards the backsheetthereby preventing any leakage through.

[0119] The cationic polysaccharides and odor controlling agents as wellas the optional absorbent gelling material if present may beincorporated as a powder, a granulate or can be sprayed in the form offor example a polysaccharide-containing solution and/or odor controllingagent-containing solution within the absorbent article. When used in agranulate or particulate form the cationic polysaccharides (e.g.,chitosan material) and odor controlling agents as well as the optionalabsorbent gelling materials may be granulated separately and then mixedtogether or granulated together.

[0120] Typical disposable absorbent articles according to the preferredembodiments of the present invention are those as described hereinafter:

Absorbent Core

[0121] According to the present invention, the absorbent can include thefollowing components: (a) an optional primary fluid distribution layerpreferably together with a secondary optional fluid distribution layer;(b) a fluid storage layer; (c) an optional fibrous (“dusting”) layerunderlying the storage layer; and (d) other optional components.According to the present invention the absorbent may have any thicknessdepending on the end use envisioned.

[0122] a Primary/Secondary Fluid Distribution Layer

[0123] One optional component of the absorbent according to the presentinvention is a primary fluid distribution layer and a secondary fluiddistribution layer. The primary distribution layer typically underliesthe topsheet and is in fluid communication therewith. The topsheettransfers the acquired fluid to this primary distribution layer forultimate distribution to the storage layer. This transfer of fluidthrough the primary distribution layer occurs not only in the thickness,but also along the length and width directions of the absorbent product.The also optional but preferred secondary distribution layer typicallyunderlies the primary distribution layer and is in fluid communicationtherewith. The purpose of this secondary distribution layer is toreadily acquire fluid from the primary distribution layer and transferit rapidly to the underlying storage layer. This helps the fluidcapacity of the underlying storage layer to be fully utilized. The fluiddistribution layers can be comprised of any material typical for suchdistribution layers. In particular fibrous layers maintain thecapillaries between fibers even when wet are useful as distributionlayers.

[0124] b Fluid Storage Layer

[0125] Positioned in fluid communication with, and typically underlyingthe primary or secondary distribution layers, is a fluid storage layer.The fluid storage layer can comprise the cationic polysaccharides andoptional absorbent gelling material. It preferably comprises thecationic polysaccharides and optional absorbent gelling materials incombination with suitable carriers.

[0126] Suitable carriers include materials, which are conventionallyutilized in absorbent structures such as natural, modified or syntheticfibers, particularly modified or non-modified cellulose fibers, in theform of fluff and/or tissues. Most preferred are tissue or tissuelaminates in the context of sanitary napkins and panty liners.

[0127] An embodiment of the absorbent structure made according to thepresent invention may comprise multiple layers comprises a double layertissue laminate formed by folding the tissue onto itself. These layerscan be joined to each other for example by adhesive or by mechanicalinterlocking or by hydrogen bridge bands. The cationic polysaccharides(together with the odor controlling agents) and optional absorbentgelling materials can be comprised between the layers.

[0128] Modified cellulose fibers such as the stiffened cellulose fiberscan also be used. Synthetic fibers can also be used and include thosemade of cellulose acetate, polyvinyl fluoride, polyvinylidene chloride,acrylics (such as Orlon), polyvinyl acetate, non-soluble polyvinylalcohol, polyethylene, polypropylene, polyamides (such as nylon),polyesters, bicomponent fibers, tricomponent fibers, mixtures thereofand the like. Preferably, the fiber surfaces are hydrophilic or aretreated to be hydrophilic. The storage layer can also include fillermaterials, such as Perlite, diatomaceous earth, Vermiculite, etc., toimprove liquid retention.

[0129] If the cationic polysaccharides and optional absorbent gellingmaterials are dispersed non-homogeneously in a carrier, the storagelayer can nevertheless be locally homogenous, i.e. have a distributiongradient in one or several directions within the dimensions of thestorage layer. Non-homogeneous distribution can also refer to laminatesof carriers enclosing cationic polysaccharides and optional absorbentgelling materials partially or fully.

[0130] c Optional Fibrous (“Dusting”) Layer

[0131] An optional component for inclusion in the absorbent coreaccording to the present invention is a fibrous layer adjacent to, andtypically underlying the storage layer. This underlying fibrous layer istypically referred to as a “dusting” layer since it provides a substrateon which to deposit absorbent gelling material in the storage layerduring manufacture of the absorbent core. Indeed, in those instanceswhere the absorbent gelling material is in the form of macro structuressuch as fibers, sheets or strips, this fibrous “dusting” layer need notbe included. However, this “dusting” layer provides some additionalfluid-handling capabilities such as rapid wicking of fluid along thelength of the pad.

[0132] d Other Optional Components of the absorbent structure

[0133] The absorbent core according to the present invention can includeother optional components normally present in absorbent webs. Forexample, a reinforcing scrim can be positioned within the respectivelayers, or between the respective layers, of the absorbent core. Suchreinforcing scrims should be of such configuration as to not forminterfacial barriers to fluid transfer. Given the structural integritythat usually occurs as a result of thermal bonding, reinforcing scrimsare usually not required for thermally bonded absorbent structures.

The topsheet

[0134] According to the present invention the absorbent articlecomprises as an essential component a topsheet. The topsheet maycomprise a single layer or a multiplicity of layers. In a preferredembodiment the topsheet comprises a first layer, which provides theuser-facing surface of the topsheet and a second layer (also calledsecondary topsheet) between the first layer and the absorbentstructure/core.

[0135] The topsheet as a whole and hence each layer individually needsto be compliant, soft feeling, and non-irritating to the wearer's skin.It also can have elastic characteristics allowing it to be stretched inone or two directions. According to the present invention the topsheetmay be formed from any of the materials available for this purpose andknown in the art, such as woven and non-woven fabrics and films.

[0136] In a preferred embodiment of the present invention at least oneof the layers, preferably the upper layer, of the topsheet comprises ahydrophobic, liquid permeable apertured polymeric film. Preferably, theupper layer is provided by a film material having apertures, which areprovided to facilitate liquid transport from the wearer-facing surfacetowards the absorbent structure. If present the lower layer preferablycomprises a non-woven layer, an apertured formed film or an air laidtissue.

[0137] The term apertured polymeric topsheet as used herein refers totopsheets comprising at least one layer or a multiplicity of layerswherein at least one layer is formed from a continuous or uninterruptedfilm material wherein apertures are created. It has been surprisinglydiscovered that apertured polymeric film topsheets yield significantlybetter odor control than other types of topsheets such as for examplethermal bonded nonwoven materials.

[0138] In general the apertured polymeric topsheet of the presentinvention is compliant, soft feeling, and non-irritating to the wearer'sskin. Further, the topsheet is fluid pervious permitting fluids (e.g.,menses and/or urine) to readily penetrate through its thickness.Suitable apertured polymeric film topsheets for use herein includepolymeric apertured formed films, thermoplastic films, apertured plasticfilms, and hydroformed thermoplastic films; porous foams; net-likereticulated foams and thermoplastic films; and thermoplastic scrims.

[0139] Preferred topsheets for use in the present invention are selectedfrom apertured formed film topsheets. Apertured formed films areespecially preferred for the topsheet because they are pervious to bodyexudates and yet non-absorbent and have a reduced tendency to allowfluids to pass back through and rewet the wearer's skin. Thus, thesurface of the formed film that is in contact with the body remains dry;thereby reducing body soiling and creating a more comfortable feel forthe wearer. Suitable formed films are described in U.S. Pat. No.3,929,135 (Thompson), issued Dec. 30, 1975; U.S. Pat. No. 4,324,246(Mullane, et al.), issued Apr. 13, 1982; U.S. Pat. No. 4,342,314 (Radel.et al.), issued Aug. 3, 1982; U.S. Pat. No. 4,463,045 (Ahr et al.),issued Jul. 31, 1984; and U.S. Pat. No. 5,006,394 (Baird), issued Apr.9, 1991. Each of these patents are incorporated herein by reference.Particularly preferred microapertured formed film topsheets aredisclosed in U.S. Pat. No. 4,609,518 (Curro et al), issue Sep. 2, 1986and U.S. Pat. No. 4,629,643 (Curro et al), issued Dec. 16, 1986, whichare incorporated by reference. The preferred topsheet for the presentinvention is the formed film described in one or more of the abovepatents and marketed on sanitary napkins by The Procter & Gamble Companyof Cincinnati, Ohio as “DRI-WEAVE.”

[0140] Suitable topsheets in the field of three-dimensional formed filmare described in EP 0 018 020 and EP 0 059 506. Especially preferred ina three dimensional formed polymeric topsheet having openings in theshape of regular pentagons which are regularly spaced and have anopening of 0.41 square millimeter. The openings are spaced 0.37 squaremillimeters apart transversely and 0.25 millimeters longitudinally. Thistopsheet has an initial opening (preforming) thickness of about 25m afinal (post forming) thickness of about 0.53 mm and an open area of from25% to about 40%.

[0141] Another formed film topsheet which is especially preferred is onehaving openings of two shapes; regular pentagons having an area of about0.21 square millimeters and an irregular hexagon having an area of 1.78square millimeters. The openings are distributed so that the distancebetween the sides of the figures is about 0.37 mm to about 0.42 mm. Thepreforming and post forming film thickness are respectively 0.25 and0.43 mm. This film has an open area of about 33.7%. Both films are madeaccording to the teachings of the above-mentioned patents.

[0142] A third form suitable topsheet comprises two separate perforatedpolymeric films superimposed one on the other.

[0143] The body surface of the formed film topsheet of the presentinvention may also be hydrophilic so as to help liquid to transferthrough the topsheet faster than if the body surface was nothydrophilic. In this manner the likelihood that menstrual fluid willflow off the topsheet rather than flowing into and being absorbed by theabsorbent structure is diminished. In a preferred embodiment, surfactantis incorporated into the polymeric materials of the formed film topsheetsuch as is described in U.S. patent application Ser. No. 07/794,745,“Absorbent Article Having A Nonwoven and Apertured Film Coversheet”filed on Nov. 19, 1991 by Aziz, et al., which is incorporated byreference. Alternatively, the body surface of the topsheet can be madehydrophilic by treating it with a surfactant such as is described in theabove referenced U.S. Pat. No. 4,950,254, incorporated herein byreference.

The Backsheet

[0144] The backsheet primarily prevents the extrudes absorbed andcontained in the absorbent structure from wetting articles that contactthe absorbent product such as underpants, pants, pyjamas andundergarments. The backsheet is preferably impervious to liquids (e.g.menses and/or urine) and is preferably manufactured from a thin plasticfilm, although other flexible liquid impervious materials can also beused. As used herein, the term “flexible” refers to materials that arecompliant and will readily conform to the general shape and contours ofthe human body. The backsheet also can have elastic characteristicsallowing it to stretch in one or two directions. In a preferredembodiment the backsheet comprises a first layer, which provides thegarment-facing surface of the backsheet and a second layer (also calledsecondary backsheet) between the first layer and the absorbentstructure/core.

[0145] The backsheet typically extends across the whole of the absorbentstructure and can extend into and form part of or all of the preferredside flaps, side wrapping elements or wings.

[0146] The backsheet can comprise a woven or nonwoven material,polymeric films such as thermoplastic films of polyethylene orpolypropylene, or composite materials such as a film-coated nonwovenmaterial. Preferably, the backsheet is a polyethylene film typicallyhaving a thickness of from about 0.012 mm (0.5 mil) to about 0.051 mm(2.0 mil).

[0147] Exemplary polyethylene films are manufactured by ClopayCorporation of Cincinnati, Ohio, under the designation P18-0401 and byEthyl Corporation, Visqueen Division, of Terre Haute, Ind., under thedesignation XP-39385. The backsheet is preferably embossed and/or mattfinished to provide a more cloth like appearance. Further, the backsheetcan permit vapors to escape from the absorbent structure, i.e. bebreathable, while still preventing exudates from passing through thebacksheet. Also breathable backsheets comprising several layers, e.g.film plus non-woven structures, can be used.

[0148] Suitable breathable backsheets for use herein include allbreathable backsheets known in the art. In principle there are two typesof breathable backsheets, single layer breathable backsheets that arebreathable and impervious to liquids and backsheets having at least twolayers, which in combination provide both breathability and liquidimperviousness.

[0149] Suitable single layer breathable backsheets for use hereininclude those described for example in GB A 2184 389, GB A 2184 390, GBA 2184 391, U.S. Pat. No. 4,591,523, U.S. Pat. No. 3,989,867 U.S. Pat.No. 3 156 242 and European Patent Application number 95120653.1.

[0150] Suitable dual or multi layer breathable backsheets for use hereininclude those exemplified in U.S. Pat. No. 3,881,489, U.S. Pat. No.4,341,216, U.S. Pat. No. 4,713,068, U.S. Pat. No. 4,818,600, EPO 203821, EPO 710 471, EPO 710 472, European Patent Application numbers95120647.3, 95120652.3, 95120653.1 and 96830097.0.

[0151] Particularly preferred are backsheets meeting the requirements asdefined in European Patent Application number 96830343.8 and morepreferably wherein the absorbent article also meets the requirements asdescribed therein.

[0152] According to the present invention the breathable backsheetcomprises at least one, preferably at least two water vapor permeablelayers. Suitable water vapor permeable layers include 2 dimensional,planar micro and macro-porous films, monolithic films, macroscopicallyexpanded films and formed apertured films. According to the presentinvention the apertures in said layer may be of any configuration, butare preferably spherical or oblong. The apertures may also be of varyingdimensions. In a preferred embodiment the apertures are preferablyevenly distributed across the entire surface of the layer, howeverlayers having only certain regions of the surface having apertures arealso envisioned. 2 dimensional planar films as used herein haveapertures having an average diameter of from 5 micrometers to 200micrometers. Typically, 2-dimensional planar micro porous films suitablefor use herein have apertures having average diameters of from 150micrometers to 5 micrometers, preferably from 120, micrometers to 10micrometers, most preferably from 90 micrometers to 15 micrometers.Typical 2 dimensional planar macroporous films have apertures havingaverage diameters of from 200 micrometers to 90 micrometers.Macroscopically expanded films and formed apertured films suitable foruse herein typically have apertures having diameters from 100micrometers to 500 micrometers. Embodiments according to the presentinvention wherein the backsheet comprises a macroscopically expandedfilm or an apertured formed film, the backsheet will typically have anopen area of more than 5%, preferably from 10% to 35% of the totalbacksheet surface area.

[0153] Suitable 2 dimensional planar layers of the backsheet may be madeof any material known in the art, but are preferably manufactured fromcommonly available polymeric materials. Suitable materials are forexample GORE-TEX (TM) or Sympatex (TM) type materials well known in theart for their application in so-called breathable clothing. Othersuitable materials include XMP-1001 of Minnesota Mining andManufacturing Company, St. Paul, Minn., USA. As used herein the term 2dimensional planar layer refers to layers having a depth of less than 1mm, preferably less than 0.5 mm, wherein the apertures have an averageuniform diameter along their length and which do not protrude out of theplane of the layer. The apertured materials for use as a backsheet inthe present invention may be produced using any of the methods known inthe art such as described in EPO 293 482 and the references therein. Inaddition, the dimensions of the apertures produced by this method may beincreased by applying a force across the plane of the backsheet layer(i.e. stretching the layer).

[0154] Suitable apertured formed films include films, which havediscrete apertures, which extend beyond the horizontal plane of thegarment-facing surface of the layer towards the core thereby formingprotuberances. The protuberances have an orifice located at theirterminating ends. Preferably said protuberances are of a funnel shape,similar to those described in U.S. Pat. No. 3, 929,135. The apertureslocated within the plane and the orifices located at the terminating endof protuberance themselves maybe circular or non circular, provided thecross sectional dimension or area of the orifice at the termination ofthe protuberance is smaller than the cross sectional dimension or areaof the aperture located within the garment facing surface of the layer.Preferably said apertured preformed films are unidirectional such thatthey have at least substantially, if not complete one directional fluidtransport towards the core. Suitable macroscopically expanded films foruse herein include films as described in for example in U.S. Pat. No.637,819 and U.S. Pat. No. 4,591,523.

[0155] Suitable macroscopically expanded films for use herein includefilms as described in for example U.S. Pat. No. 4,637,819 and U.S. Pat.No. 4,591,523.

[0156] Suitable monolithic films include Hytrel™, available from DuPontCorporation, USA, and other such materials as described in Index 93Congress, Session 7A “Adding value to Nonwovens”, J- C. Cardinal and Y.Trouilhet, DuPont de Nemours International S. A., Switzerland.

[0157] According to the present invention the backsheet may comprise inaddition to said water vapor permeable layer additional backsheetlayers. Said additional layers may be located on either side of saidwater vapor permeable layer of the backsheet. The additional layers maybe of any material, such as fibrous layers or additional water vaporpermeable layers as described herein above.

Odor Control Test

[0158] The odor reduction is measured by for example an in vitro snifftest. In vitro sniff test consists in analyzing by expert graders theodor associated with articles comprising the ingredients to be tested(including references articles) when contacted with an odorouscomponents-containing solution

[0159] The expert graders express their judgment about (un)pleasantnessof the odor using a (un)pleasantness scale, typically from −10 (highestlevel of unpleasantness) to 5 (most pleasant). With this procedure, eachgrader compares MU (Unpleasantness) in the test session. The relative MUodor values from different products are assigned numbers. For example,in a test session, a sample that is perceived to be twice as strong asanother is assigned twice as large a number. One that is perceived to beone-tenth as strong as another is assigned a number one-tenth as large,etc. In each test session, zero is used to designate neutral hedonicity,and + and − numbers are assigned in ratio proportion to the relativepleasantness and unpleasantness of the odor.

[0160] Surprisingly in vitro in-house sniff tests conducted by using anin-house odorous components-containing solution reproducing theessential malodorous characteristics of menses showed synergistic odorreduction when comparing chitosan (e.g. chitosonium pyrrolidonecarboxylate (Kytamer®) together with an odor controlling agent accordingto the present invention (e.g., zeolite A, Wessalith CS, available fromDegussa AG, or ethylenediamine tetracetate (BASF) or hydroxypropylbeta-cyclodextrin (Fluka)) to each of these ingredients taken alone atthe same total level of active. Indeed the % of unpleasantness reductionobtained for the mixture was higher than the % of unpleasantnessreduction obtained for each of the two ingredients used alone at thesame total level of active. The Unpleasantness values, for each sample,were obtained as a mean of at least 15 observations (3 products, 5graders). These results were statistically significant. Alternativelythe odor reduction can also be measured with in vivo sniff tests asdescribed in patent applications, EP-A-811387 or WO97/4619 1, hereinincorporated by reference. The present invention is further illustratedby the following examples.

EXAMPLES Example A

[0161] The feminine pads used in the following examples were Always(Always is a registered Trade Mark) as sold by the Procter & GambleCompany.

[0162] Each feminine pad was opened by cutting the wrap around theperforated coverstock at its bottom face approximately along alongitudinal edge of the release paper, which covers the externaladhesive layer. The side of the absorbent fibrous core was then exposedby slightly shifting the water impermeable plastic bottom layer andsubsequently, the fibrous core was split into two halves, each havingapproximately the same thickness, along a plane, which is parallel tothe plane of the pad itself. Chitosan material and odor controllingagent were homogeneously distributed between the two fibrous layers.

[0163] The water impermeable inner backsheet was then put back into itsoriginal position and the wrap around perforated coverstock was sealedalong the cut by means of e.g. a double-sided adhesive tape.

[0164] The chitosan powder material used was 0.2g of chitosoniumpyrrolidone carboxylate, commercially available from AmercholCorporation, Edison, N.J. under the name Kytamer® PC.

[0165] The odor-controlling agent used was 0.3g of Zeolite A, WessalithCS, available from Degussa AG.

Example B

[0166] Other pads were prepared by following the method in Example Aexcept that the odor-controlling agent used was cyclodextrin instead ofzeolite. The cyclodextrin used was 0.1 g of hydroxypropylbeta-cyclodextrin commercially available from Fluka.

Example C

[0167] Other pads were prepared by following the method in Example Aexcept that the odor-controlling agent used was a chelating agentinstead of zeolite. The chelating agent used was 0.1 g ofethylenediamine tetracetate commercially available from BASF AG.Examples D, E and F Other pads were prepared by following the method inrespectively Examples A, B, and C except that an absorbent gellingmaterial (AGM) was homogeneously distributed between the two fibrouslayer beside the chitosan material and odor controlling agent usedrespectively in Examples A, B and C.

[0168] The AGM used was 0.4 g of cross-linked sodium polyacrylate Xz9589001, available from Dow Chemicals.

Examples G, H and I

[0169] Other pads were prepared by following the method in respectivelyExamples A, B and C except that after having split the fibrous core intotwo halves, an absorbent gelling material (AGM) and the odor controllingagent as defined in respectively Examples A, B and C, were respectivelyhomogeneously distributed between the two halve fibrous layers and thechitosan material was homogeneously distributed onto the lower halvefibrous layer (i.e., the one intended to be closer to the backsheet ofthe pad once reconstituted). Actually a solution of chitosan materialwas prepared and homogeneously sprayed onto the inner side of the lowerhalve fibrous layer.

[0170] The chitosan solution was prepared by solubilizing 1 g ofchitosonium pyrrolidone carboxylate commercially available from AmercholCorporation under the name Kytamer® PC in 100 g of distilled water andstirring at 40° C. over 1 night. 10 g of the prepared solution wassprayed onto the lower halve of the fibrous layer (i.e., 0.1 g ofchitosan per pad) AGM used was 0.4 g of cross-linked sodiumpolyacrylate, commercially available from Dow Chemicals (code:XZ9589001).

[0171] The odor controlling agents used (type and amount) were the onesrespectively defined in Examples A, B and C.

[0172] Accordingly various pads were made respectively corresponding toExamples G, H and I with different odor controlling agents,corresponding respectively to the odor controlling agents used inExamples A, B and C described herein above.

Example J

[0173] The feminine pantiliner used in the following examples is amodified panty liner based on Always “Alldays Duo Active” manufacturedby Procter & Gamble, Germany. The topsheet is a film/non woven composite{film supplier code BPC 5105 CPM BP Chemical Germany, non-woven suppliercode ARBO TB/BI Mequinenza Spain}. The core material is a tissuelaminate (13.2 cm×4.0 cm) composed of a 2 layers of air laid tissue of55 g/m² basis weight {available from Unikay Italy under the suppliercode Unikay 303 LF}. Between the two tissue layers the laminate containschitosan material together with an odor-controlling agent.

[0174] The backsheet comprises two layers a first layer and a secondlayer. The first layer is in contact with the absorbent tissue and thesecond layer. The second layer is in contact with the first layer andthe undergarment of the wearer. The first layer is a formed aperturedfilm (CPT) made of Low Density PE {supplied by Tredegar Film Products B.V. Holland under the manufacturing code X-1522}. The second layer iscomposed of a nonwoven laminate {13 MB/16SB manufactured by Corovin GmbHin Germany under the trade name MD 2005}. The nonwoven laminate iscomposed of 16 g/m² spun bond and 13 g/m² meltblown. Each backsheetlayer is joined over the full surface by an extensively overlappedspiral glue application at a basis weight of approximately 8 g/m². Theglue utilized for attachment of both backsheet layers was supplied bySAVARE' SpA. Italy (under the material code PM 17).

[0175] The chitosan material used was 0.2 g of chitosonium pyrrolidonecarboxylate, commercially available from Amerchol Corporation, Edison,N.J. under the name Kytamer® PC. The odor controlling agent used waseither 0.3 g of Zeolite A, Wessalith CS, available from Degussa AG, or0.1 g of hydroxypropyl beta-cyclodextrin commercially available fromFluka, or 0.1 g of ethylenediamine tetracetate (EDTA) commerciallyavailable from BASF AG. Other panty liners can be made starting from theones exemplified in Example J above except that AGM is incorporated ontop of the chitosan material and odor-controlling agent. Indeed the 3classes of ingredients were homogeneously mixed together to obtain apowder that was homogeneously distributed between the two layers of thelaminate. AGM used was 0.4g of cross-linked sodium polyacrylate,commercially available from Dow Chemicals (code:XZ 9589001).

[0176] All the above exemplified pads and pantiliners deliveredoutstanding odor control properties towards malodorous compoundsassociated with bodily fluids.

What is claimed is:
 1. An article comprising as an odour control systemfor controlling odours, preferably odours associated with bodily fluid,a cationic polysaccharide together with an odor controlling agent.
 2. Anarticle according to claim 1 wherein the cationic polysaccharide is anaminopolysaccharide selected from the group consisting of chitosan,chitosan salt, modified chitosan, crosslinked chitosan and mixturesthereof.
 3. An article according to claim 1 wherein said cationicpolysaccharide is a chitosan material having a degree of deacetylationof more than 75%.
 4. An article according to claim 1 wherein thechitosan material is a chitosan salt, a chitosan salt of citric acid,formic acid, acetic acid, N-acetylglycine, acetylsalicylic acid, fumaricacid, glycolic acid, iminodiacetic acid, itaconic acid, lactic acid,maleic acid, malic acid, nicotinic acid, salicylic acid, succinamicacid, succinic acid, ascorbic acid, aspartic acid, glutamic acid,glutaric acid, malonic acid, pyruvic acid, sulfonyldiacetic acid,benzoic acid, epoxysuccinic acid, adipic acid, thiodiacetic acid,thioglycolic acid, alanine, valine, leucine, isoleucine,prolinephenylalanine, triptofane, metionine, glycine, serine, cysteine,tyrosine, asparagine, glutamine, lysine, arginine, istydine,hydroxyproline, pyrrolidone carboxylic acid, chitosonium pyrrolidonecarboxylate and mixtures thereof.
 5. An article according to claim 1which comprises from about 0.5 gm⁻² to about 500 gm⁻² of cationicpolysaccharide or a mixture thereof.
 6. An article according to claim 1wherein the odor controlling agent is a chelating agent and/or an odorabsorbent agent.
 7. An article according to claim 6 wherein said odorcontrolling agent is an odor absorbent agent selected from the groupconsisting of zeolites, carbons, diatomaceous earth, starches,cyclodextrin and derivatives thereof, kieselguhr, clays, ion exchangeresins and combination thereof and preferably is zeolite,alpha-cyclodextrin, beta-cyclodextrin, gamma-cyclodextrin or aderivative thereof or a combination thereof.
 8. An article according toclaim 6 wherein the odor controlling agent is a chelating agent selectedfrom the group consisting of phosphonate chelating agents, aminophosphonate chelating agents, polyfunctionally-substituted aromaticchelating agents, amino carboxylate chelating agents, other chelatingagents like ethylene diamine N,N′-disuccinic acid, aspartic acid,glutamic acid, malonic acid, glycine and mixtures thereof.
 9. An articleaccording to claim 8 wherein the chelating agent is selected from thegroup consisting of ethylene diamine tetracetate, -triacetate,-diacetate, and -monoacetate, ethylenediamine N,N,-disuccinic acid,ethylenediamine penta (methylene phosphonic acid), ethylenediamine tetra(methylene phosphonic acid) and mixtures thereof and more preferably isethylene diamine tetracetate.
 10. An article according to claim 1 whichcomprises from about 1 to about 600 gm⁻² of the odor controlling agentor a mixture thereof.
 11. An article according to claim 6 whichcomprises from about 1 to about 600 gm⁻² of the odor controlling agentor a mixture thereof.
 12. An article according to claim 1 furthercomprising an absorbent gelling material.
 13. An article according toclaim 6 further comprising an absorbent gelling material.
 14. An articleaccording to claim 12, wherein the absorbent gelling material is presentat a level from about 5 gm⁻² to about 250 gm⁻².
 15. An article accordingto claim 13, wherein the absorbent gelling material is present at alevel from about 5 gm⁻² to about 250 gm⁻².
 16. An article according toclaim 1 wherein said article is a disposable absorbent article selectedfrom the group consisting of a sanitary napkin, a pantiliner, a tampon,a diaper, an incontinent pad, a breast pad, a perspiration pad, a humanor animal waste management device, an interlabial pad or a bodycleansing article.
 17. An article according to claim 16 wherein saidarticle is a disposable absorbent article comprising a liquid pervioustopsheet, a backsheet and an absorbent core intermediate said backsheetand said topsheet.
 18. An article according to claim 6 wherein saidarticle is a disposable absorbent article selected from the groupconsisting of a sanitary napkin, a pantiliner, a tampon, a diaper, anincontinent pad, a breast pad, a perspiration pad, a human or animalwaste management device, an interlabial pad or a body cleansing article.19. An article according to claim 18 wherein said article is adisposable absorbent article comprising a liquid pervious topsheet, abacksheet and an absorbent core intermediate said backsheet and saidtopsheet.